A modern-day Lascaux cave underneath Paris.

The ruins of a Duke's bucolic dream, where camels once roamed alongside "Dutch" windmills and faux-Italian vineyards.

High atop the Eiffel Tower is a small apartment built exclusively to entertain the science elite and make the rest of Paris jealous.

This charming cobbled backstreet is the most Instagramable street in Paris, much to the residents' annoyance.

Once thought to be the mysterious work of a witchy prophetess, a well with unusual properties turns objects into "stone".

A 600-year-old mini shrine guarded by a sword-wielding knight hides in a crumbling cliff face.

The final resting place of England's most notorious bandit.

The National Railway Museum in York is the largest railway museum in the world, attracting almost 1 million visitors per year.

Follow the original medieval paths that wind through this intriguing section of the city.

This memorial to World War II's fallen airmen shows us the movements of the stars that once guided them.

This sculpture marks the spot where one of the greatest Roman rulers was proclaimed emperor.

A Reformation-era fiery figurehead once denoted this location as a print shop.

This tipsy office building in downtown Prague was originally called “Fred and Ginger.”

A bust of Franz Kafka spins in pieces, reflecting the writer's inner torment.

Around 100,000 bodies are buried below the medieval headstones, many of which mark graves with multiple bodies stacked up to 12 deep.

Macabre astrological automaton clock dating to the late 1400s.

These eight mummies are the best-preserved human remains ever discovered in North America.

Neon artworks light up this dark Edinburgh tunnel.

Poetic, metallic giraffes adorn a square off an Edinburgh thoroughfare.

Inside this cathedral is a shoulder bone belonging to the Patron Saint of Scotland.

A statue in the heart of Edinburgh honors a bear that served in the Polish military during World War II.

A 18th century graveyard and its astonishing cortege of macabre iconography.

This sculpture of disembodied body parts forms a poignant memory of the horrors of World War II.

One of the oldest scientific gardens in Britain, containing more than 13,302 plant species in its core collection.